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ENS 40665 | 11 April 2004 04:43:00 | THIS IS AN 8-HOUR NOTIFICATION TO REPORT A VALID ESF SIGNAL TO START 1C EMERGENCY DIESEL GENERATOR THAT OCCURRED ON 4/11/04 AT 0023. Salem Unit 1 is defueled. The spent fuel pool cooling system is providing decay heat removal. Spent fuel pool temperature is being maintained at 106 degrees. RCS temperature is 75 degrees. The RCS is vented to atmosphere. Reactor level is 97.5 feet. 1C emergency diesel generator is cleared and tagged for maintenance. 13 station power transformer was returned to service on 4/10/04 at 2347. The operating crew briefed expected response and abnormal procedures if the 4kv vital bus did not transfer during the retest of 13 station power transformer. Operations successfully retested 1A and 1B 4kv vital bus transfer from 14 station power transformer to 13 station power transformer and back to 14 station power transformer in accordance with station operating procedures. Operations attempted to retest the 1C 4kv vital bus transfer from 14 station power transformer to 13 station power transformer. When the operator attempted to close 13CSD in feed breaker, the 14CSD in feed breaker opened as designed, but 13CSD breaker failed to close. The 1C 4kv vital bus deenergized due to both offsite power source in feed breakers opening and 1C emergency diesel generator unavailable. An ESF signal to start the 1C emergency diesel generator was provided by the safeguards equipment cabinet (SEC). Since the 1C emergency diesel was cleared and tagged for maintenance, it did not start. The cause of the failure to transfer is not known at this time. The operating crew implemented the appropriate abnormal operating procedures for the de-energized 1C 4kv vital bus. Operator and plant response was as expected. Decay heat continues to be removed by the spent fuel pool cooling system. Outage incident response team is evaluating and troubleshooting the cause of the loss of power to 1C 4kv vital bus. ORAM risk remains yellow. There were no personnel injured during the event. The licensee will inform Lower Alloways Creek (LAC) Township and the NRC Resident Inspector.
The licensee provided the following information via facsimile: On April 11, 2004 at 0023 PSEG made an 8 hour notification to report a valid ESF actuation of the 1 'C' Emergency Diesel Generator (Event Number 40665). At the time of the event Salem Unit 1 was defueled. The spent: fuel pool cooling system was providing decay heat removal and spent fuel pool temperature was being maintained at 106 degrees. RCS temperature was 75 degrees and the RCS was vented to atmosphere. The 1 'C' EDG was cleared and tagged for maintenance. The 13 Station Power Transformer (SPT) had been returned to service on 4/10/04 at 2347. The operating crew was briefed on the expected response and reviewed the abnormal procedures if the 4kv vital bus did not transfer during the retest of 13 SPT. Operations successfully retested 1 'A' and 1 "B" 4kv vital bus transfer from 14 SPT to 13 SPT and back to 14 SPT in accordance with station operating procedures. When Operations attempted to retest the 1 'C' 4kv vital bus transfer from 14 SPT to 13 SPT, the 14 SPT in feed breaker opened as designed, but 13 SPT breaker failed to close and the 1 'C' 4kv vital bus de-energized. A signal to start the 1 "C" EDG was provided by the safeguards equipment cabinet (SEC), because the 1 'C' EDG was cleared and tagged for maintenance it did not start. Decay heat continued to be removed by the spent fuel pool cooling system. Subsequent Investigation into this event and further review of NUREG 1022 has determined that the condition described above is not reportable under the requirements of I0CFR50.72(b)(3)(iv) or 50.73(a)(2)(iv). NUREG-1022, section 3.2.6 states that valid signals are those signals that are initiated in response to actual plant conditions or parameters satisfying the requirements for initiation of the safety function of the system. In this case, plant conditions were such that it did not require the 1 'C' EDG to be capable of starting and loading automatically in response to an undervoltage signal. The reactor was defueled and spent fuel cooling system providing fuel cooling was unaffected by the event. NUREG-1022 states that train level actuations are reportable. However, in this instance, the EDG did not actuate because it was removed from service and was not required to be operable. NUREG-1022 states that single component actuations are typically not reportable because single components of complex systems, by themselves, usually do not mitigate the consequences of significant events. With the 1 'C' EDG removed from service, the 1 'C' bus undervoltage signal is not sufficient to complete the full actuation logic to mitigate the event. Therefore this event was not reportable under 10CFR50.72 or 50.73, as per the guidance provided in NUREG 1022. The licensee will notify the NRC Resident Inspector. Notified R1DO (Richard Conte) |